Portable Acceleration of CMS Computing Workflows with Coprocessors as a Service

Computing demands for large scientific experiments, such as the CMS experiment at the CERN LHC, will increase dramatically in the next decades. To complement the future performance increases of software running on central processing units (CPUs), explorations of coprocessor usage in data processing hold great potential and interest. Coprocessors are a class of computer processors that supplement CPUs, often improving the execution of certain functions due to architectural design choices. We explore the approach of Services for Optimized Network Inference on Coprocessors (SONIC) and study the deployment of this as-a-service approach in large-scale data processing. In the studies, we take a data processing workflow of the CMS experiment and run the main workflow on CPUs, while offloading several machine learning (ML) inference tasks onto either remote or local coprocessors, specifically graphics processing units (GPUs). With experiments performed at Google Cloud, the Purdue Tier-2 computing center, and combinations of the two, we demonstrate the acceleration of these ML algorithms individually on coprocessors and the corresponding throughput improvement for the entire workflow. This approach can be easily generalized to different types of coprocessors and deployed on local CPUs without decreasing the throughput performance. We emphasize that the SONIC approach enables high coprocessor usage and enables the portability to run workflows on different types of coprocessors.

Measurement of Energy Correlators inside Jets and Determination of the Strong Coupling α_{S}(m_{Z})

Energy correlators that describe energy-weighted distances between two or three particles in a hadronic jet are measured using an event sample of sqrt[s]=13  TeV proton-proton collisions collected by the CMS experiment and corresponding to an integrated luminosity of 36.3  fb^{-1}. The measured distributions are consistent with the trends in the simulation that reveal two key features of the strong interaction: confinement and asymptotic freedom. By comparing the ratio of the measured three- and two-particle energy correlator distributions with theoretical calculations that resum collinear emissions at approximate next-to-next-to-leading-logarithmic accuracy matched to a next-to-leading-order calculation, the strong coupling is determined at the Z boson mass: α_{S}(m_{Z})=0.1229_{-0.0050}^{+0.0040}, the most precise α_{S}(m_{Z}) value obtained using jet substructure observables.

Observation of Strong Nuclear Suppression in Exclusive J/ψ Photoproduction in Au+Au Ultraperipheral Collisions at RHIC

We report a measurement of exclusive J/ψ and ψ(2s) photoproduction in Au+Au ultraperipheral collisions at sqrt[s_{NN}]=200  GeV using the STAR detector. For the first time, (i) the ψ(2s) photoproduction in midrapidity at the Relativistic Heavy-Ion Collider has been experimentally measured; (ii) nuclear suppression factors are measured for both the coherent and incoherent J/ψ production. At average photon-nucleon center-of-mass energy of 25.0 GeV, the coherent and incoherent J/ψ cross sections of Au nuclei are found to be 71±10% and 36±7%, respectively, of that of free protons. The stronger suppression observed in the incoherent production provides a new experimental handle to study the initial-state parton density in heavy nuclei. Data are compared with theoretical models quantitatively.

The impact of sink removal and other water-free interventions in intensive care units on water-borne healthcare-associated infections: a systematic review

With increasing awareness of water sinks as potential sources of outbreaks and transmission of multi-drug resistant (MDR) bacteria in intensive care units (ICUs), there is growing interest in water-free patient care systems. This systematic review reviewed and synthesized available evidence on the effectiveness of sink removal with or without water-free activities in the ICU environment to reduce water-borne healthcare-associated infections. We searched five databases (PubMed, MEDLINE, Scopus, Web of Science and Embase) for studies published from 1st January 1980 to 2nd April 2024 that examined water-less or water-free activities in the ICU to reduce healthcare-associated infections and patient colonization. Of 2075 articles, seven quasi-experimental studies (total: 332 patient beds) met the study selection criteria. Six of these seven studies (85.7%) were based in adult ICUs; one (14%) was in a neonatal ICU. Five of seven sites (71.4%) implemented water-less interventions after an outbreak. Water-free alternatives used included water-less bath products (six of seven; 85.7%), bottled water for consumption (three of seven; 42.9%), oral care (three of seven; 42.9%) and dissolving of oral medication (four of seven; 57.1%), designated 'contaminated' sink outside of patient and medication preparation areas for disposal of wastewater (four of seven; 57.1%). Implicated pathogens studied included MDR Gram-negative bacteria (four of seven; 57.1%), MDR Pseudomonas aeruginosa only (two of seven; 28.6%), and pulmonary non-tuberculous mycobacterium (NTB) (one of seven; 14.3%). Five of seven (71.4%) studies reported outbreak cessation. Preliminary evidence, from a limited number of studies of which the majority were conducted in an outbreak setting, suggest that sink removal and other water-free interventions in the ICU helped terminate outbreaks involving taps and decrease hospital-onset respiratory isolation of pulmonary NTB.

Electron cyclotron emission calibration with Thomson scattering using a wide scan of toroidal magnetic field of KSTAR

The Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak is capable of operating at a wide range of toroidal magnetic fields up to 3.5 T at the major radius. The electron cyclotron emission (ECE) diagnostic on KSTAR is required to cover a broad frequency range for electron temperature profile measurements in both the low and high field sides. To meet these broadband requirements, the ECE system consists of W-band (78-110 GHz) and D-band (110-162 GHz) heterodyne radiometers. The two radiometers are connected to 28 and 48 detection channels, respectively. However, since the absolute ECE calibration based on the hot-cold calibration has been very challenging, an alternative method of calibration was performed using Thomson scattering measurements and varying toroidal magnetic fields. As the toroidal magnetic field is scanned from 1.6 to 3.2 T in steps of 0.2 T, most of the 76 ECE channels are calibrated relatively by the electron temperature values of Thomson scattering in a narrow region (0.2 < r/a <0.6). In this article, the methodological details of the ECE calibration are described. In addition, to demonstrate the robustness of the ECE calibration factors, the calibrated electron temperature profiles from ECE measurements are compared with the ion temperature profiles in terms of the plasma position as the plasma positon shifts outward.

Search for Narrow Trijet Resonances in Proton-Proton Collisions at sqrt[s]=13 TeV

The first search for singly produced narrow resonances decaying to three well-separated hadronic jets is presented. The search uses proton-proton collision data corresponding to an integrated luminosity of 138  fb^{-1} at sqrt[s]=13  TeV, collected at the CERN LHC. No significant deviations from the background predictions are observed between 1.75 and 9.00 TeV. The results provide the first mass limits on a right-handed boson Z_{R} decaying to three gluons and on an excited quark decaying via a vector boson to three quarks, as well as updated limits on a Kaluza-Klein gluon decaying via a radion to three gluons.

Optimized collection optic design for divertor Thomson scattering diagnostics in KSTAR

Last year, the KSTAR divertor material was changed from carbon to tungsten tiles. An optimized collection optic design for divertor Thomson scattering diagnostics in KSTAR was conducted for electron temperature (1-100 eV) and electron density (1 × 1018-1 × 1019 m-3) profile diagnostics. This diagnostic system will utilize a 1064 nm Nd:YAG laser directly from the K-top port toward the beam dump located at K-bottom, while collecting scattered light from five spatial points in the divertor area via collection optics situated in the j-middle port. Given spatial limitations, the solid angle of measurement points is limited, and the collection optic design facing the tungsten divertor is susceptible to stray light. So, the design of the collection optic is important for divertor Thomson scattering diagnostics. For optimal performance, we performed two types of collection optic designs: Cooke-triplet and double-Gaussian. We present performance ray tracing analysis results for both designs and derive the optimal design.

Mortality risk in patients with preserved ratio impaired spirometry: assessing the role of physical activity

BACKGROUND

While all-cause mortality is reportedly increased in preserved ratio impaired spirometry (PRISm), no remedial efforts have been suggested.

AIM

To study the ability of physical activity (PA) on reducing the morality increased in PRISm patients.

DESIGN

We prospectively enrolled a cohort of Taiwanese adults from 1994 to 2018 in a health surveillance program.

METHODS

Mortality risks of those who were inactive were compared against those meeting the current recommendation of 150 min/week of PA. Cox proportional hazards models were used for hazard ratios and life table method was for estimating loss of life expectancy.

RESULTS

A total of 461 183 adults were enrolled. Among them, one-seventh of the cohort (65 832 or 14.3%) had PRISm, and 53.1% were inactive. Those who were inactive with PRISm had 28% increased mortality from all-cause, 45% from cardiovascular diseases (CVDs) and 67% from respiratory disease, with a 3-year reduction in life expectancy (males, 3.72 and females, 2.93). In PRISm patients who met the exercise recommendation, excess mortality was reduced by two-third, both all-cause (from 28% to 9%) and CVD (from 45% to 15%).

CONCLUSION

PRISm involves a large portion of general population (14.3%) and shortens life expectancy by 3 years. More than half of the subjects were physically inactive, and adherence to 150 min/week of PA was associated with a two-third reduction of excess mortality from all cause and from CVD. Recommending PA among those with PRISm might be highly beneficial, although exercise alone may not eliminate all risks associated with PRISm.

Search for Baryon Number Violation in Top Quark Production and Decay Using Proton-Proton Collisions at sqrt[s]=13 TeV

A search is presented for baryon number violating interactions in top quark production and decay. The analysis uses data from proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC with an integrated luminosity of 138  fb^{-1}. Candidate events are selected by requiring two oppositely charged leptons (electrons or muons) and exactly one jet identified as originating from a bottom quark. Multivariate discriminants are used to separate the signal from the background. No significant deviation from the standard model prediction is observed. Upper limits are placed on the strength of baryon number violating couplings. For the first time the production of single top quarks via baryon number violating interactions is studied. This allows the search to set the most stringent constraints to date on the branching fraction of the top quark decay to a lepton, an up-type quark (u or c), and a down-type quark (d, s, or b). The results improve the previous bounds by 3 to 6 orders of magnitude based on the fermion flavor combination of the baryon number violating interactions.

Highest fusion performance without harmful edge energy bursts in tokamak

The path of tokamak fusion and International thermonuclear experimental reactor (ITER) is maintaining high-performance plasma to produce sufficient fusion power. This effort is hindered by the transient energy burst arising from the instabilities at the boundary of plasmas. Conventional 3D magnetic perturbations used to suppress these instabilities often degrade fusion performance and increase the risk of other instabilities. This study presents an innovative 3D field optimization approach that leverages machine learning and real-time adaptability to overcome these challenges. Implemented in the DIII-D and KSTAR tokamaks, this method has consistently achieved reactor-relevant core confinement and the highest fusion performance without triggering damaging bursts. This is enabled by advances in the physics understanding of self-organized transport in the plasma edge and machine learning techniques to optimize the 3D field spectrum. The success of automated, real-time adaptive control of such complex systems paves the way for maximizing fusion efficiency in ITER and beyond while minimizing damage to device components.

Anesthesia for a Patient with Undiagnosed Myotonic Dystrophy

ABSTRACT

Myotonic dystrophy (DM) is an autosomal dominant genetic disorder characterized by progressively worsening loss of muscle mass and weakness. Anesthesiologists face challenges in managing these patients due to risks such as prolonged intubation and delayed recovery associated with anesthesia in such conditions. We report a case of a 40-year-old male patient undergoing open total gastrectomy under general anesthesia. After the surgery, we administered sugammadex to reverse neuromuscular blockade and confirmed the patient's spontaneous breathing. We then proceeded to extubate the patient. However, the patient experienced complications such as apnea, desaturation, and mental changes. The patient was re-intubated and transferred to the intensive care unit for ventilator support. He was diagnosed with DM by genetic test later. Poor preoperative assessment or undiagnosed DM in surgical patients can lead to severe complications. Thus, it is important to carefully check preoperative laboratory results, patient history, and physical findings.

Observation of WWγ Production and Search for Hγ Production in Proton-Proton Collisions at sqrt[s]=13 TeV

The observation of WWγ production in proton-proton collisions at a center-of-mass energy of 13 TeV with an integrated luminosity of 138  fb^{-1} is presented. The observed (expected) significance is 5.6 (5.1) standard deviations. Events are selected by requiring exactly two leptons (one electron and one muon) of opposite charge, moderate missing transverse momentum, and a photon. The measured fiducial cross section for WWγ is 5.9±0.8(stat)±0.8(syst)±0.7(modeling)  fb, in agreement with the next-to-leading order quantum chromodynamics prediction. The analysis is extended with a search for the associated production of the Higgs boson and a photon, which is generated by a coupling of the Higgs boson to light quarks. The result is used to constrain the Higgs boson couplings to light quarks.

New Structures in the J/ψJ/ψ Mass Spectrum in Proton-Proton Collisions at sqrt[s]=13 TeV

A search is reported for near-threshold structures in the J/ψJ/ψ invariant mass spectrum produced in proton-proton collisions at sqrt[s]=13  TeV from data collected by the CMS experiment, corresponding to an integrated luminosity of 135  fb^{-1}. Three structures are found, and a model with quantum interference among these structures provides a good description of the data. A new structure is observed with a local significance above 5 standard deviations at a mass of 6638_{-38}^{+43}(stat)_{-31}^{+16}(syst)  MeV. Another structure with even higher significance is found at a mass of 6847_{-28}^{+44}(stat)_{-20}^{+48}(syst)  MeV, which is consistent with the X(6900) resonance reported by the LHCb experiment and confirmed by the ATLAS experiment. Evidence for another new structure, with a local significance of 4.7 standard deviations, is found at a mass of 7134_{-25}^{+48}(stat)_{-15}^{+41}(syst)  MeV. Results are also reported for a model without interference, which does not fit the data as well and shows mass shifts up to 150 MeV relative to the model with interference.

Utility of cranial MRI in non-traumatic headache patients with prior negative head CT within 1 month

AIM

To investigate the importance of additional cranial magnetic resonance imaging (cMRI) in non-traumatic headache patients with a prior negative head computed tomography (CT) examination within 1 month.

MATERIALS AND METHODS

This retrospective study analysed 162 adult patients with non-traumatic headache who underwent cMRI within 1 month of a negative initial head CT at the emergency department (ED). The diagnostic yield and false-referral rate were analysed according to the revisit duration (early [≤1 week] versus late [>1-4 weeks] revisits), patient care settings (ED versus outpatient clinics [OPC]), and clinical variables. Subsequent patient management change (PMC), such as admission and treatment (AT) or outpatient clinic treatment (OT), were also investigated.

RESULTS

The overall diagnostic yield of cMRI was 17.3% (28/162) and the false-referral rate was 1.2% (2/162). The diagnostic yield of cMRI was significantly different according to the patient care settings (ED, 24.7% [21/85] versus OPC, 9.1% [7/77]; p=0.02). The diagnostic yield was highest in the ED-early-revisit group (25.4% [18/71]), 45% (9/20) in those with systemic signs, and 46.7% (14/30) in those with symptom change. Among patients with positive cMRI findings, 90% (27/30) received AT and 3.3% (1/30) received OT. Among OPC-revisit-negative cMRI patients, PMC occurred in 0% (0/50).

CONCLUSION

The diagnostic yield of cMRI was relatively high for headache patients who revisited the ED earlier, especially in those with systemic signs or symptom change. Most positive cMRI cases experienced PMC. Negative cMRI in OPC-revisit patients might help clarify the benign nature of a condition.

Search for Scalar Leptoquarks Produced via τ-Lepton-Quark Scattering in pp Collisions at sqrt[s]=13 TeV

The first search for scalar leptoquarks produced in τ-lepton-quark collisions is presented. It is based on a set of proton-proton collision data recorded with the CMS detector at the LHC at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 138  fb^{-1}. The reconstructed final state consists of a jet, significant missing transverse momentum, and a τ lepton reconstructed through its hadronic or leptonic decays. Limits are set on the product of the leptoquark production cross section and branching fraction and interpreted as exclusions in the plane of the leptoquark mass and the leptoquark-τ-quark coupling strength.

Factors associated with survival of patients with advanced lung cancer and long travel distances

BACKGROUND/PURPOSE

Patients with advanced cancer sometimes travel to locations that have the treatment that they need. We explored the prognostic factors of survival in patients with advanced lung cancer who travel long distances in Taiwan.

METHODS

We obtained data from the National Taiwan University Hospital (NTUH) Integrated Medical Database. Patients who received a diagnosis of stage IV lung cancer from 2010 to 2019 and were treated in NTUH and its Hsinchu and Yunlin branches were enrolled. Factors associated with survival were analyzed using a Cox hazard regression model.

RESULTS

In total, 6178 patients with stage IV lung cancer were enrolled. Young age, female sex, smaller primary tumor size, better performance, and non-squamous cell non-small cell histology were independently associated with longer survival. Treatment in medical centers and long travel distances (>50 km) were associated with longer survival in the univariate analysis but not in the multivariate analysis (hazard ratio [HR]: 1.04, p = 0.361; HR: 0.99, p = 0.775, respectively). Participation in clinical trials was associated with longer survival in the univariate (HR: 0.53, p < 0.001) and multivariate analyses (HR: 0.62, p < 0.001). For the 1144 patients in the Hsinchu area, enrolment in clinical trials was an independent prognostic factor (HR: 0.72, p = 0.040), whereas treatment in medical centers was not (HR: 0.95, p = 0.635).

CONCLUSION

Long travel distances and treatment in medical centers were not independently associated with survival for patients with advanced lung cancer. Enrolment in clinical trials was an independent prognostic factor.

Search for Inelastic Dark Matter in Events with Two Displaced Muons and Missing Transverse Momentum in Proton-Proton Collisions at sqrt[s]=13 TeV

A search for dark matter in events with a displaced nonresonant muon pair and missing transverse momentum is presented. The analysis is performed using an integrated luminosity of 138  fb^{-1} of proton-proton (pp) collision data at a center-of-mass energy of 13 TeV produced by the LHC in 2016-2018. No significant excess over the predicted backgrounds is observed. Upper limits are set on the product of the inelastic dark matter production cross section σ(pp→A^{'}→χ_{1}χ_{2}) and the decay branching fraction B(χ_{2}→χ_{1}μ^{+}μ^{-}), where A^{'} is a dark photon and χ_{1} and χ_{2} are states in the dark sector with near mass degeneracy. This is the first dedicated collider search for inelastic dark matter.

A novel computer-assisted tool for 3D imaging of programmed death-ligand 1 expression in immunofluorescence-stained and optically cleared breast cancer specimens

BACKGROUND

Programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) are the two most common immune checkpoints targeted in triple-negative breast cancer (BC). Refining patient selection for immunotherapy is non-trivial and finding an appropriate digital pathology framework for spatial analysis of theranostic biomarkers for PD-1/PD-L1 inhibitors remains an unmet clinical need.

METHODS

We describe a novel computer-assisted tool for three-dimensional (3D) imaging of PD-L1 expression in immunofluorescence-stained and optically cleared BC specimens (n = 20). The proposed 3D framework appeared to be feasible and showed a high overall agreement with traditional, clinical-grade two-dimensional (2D) staining techniques. Additionally, the results obtained for automated immune cell detection and analysis of PD-L1 expression were satisfactory.

RESULTS

The spatial distribution of PD-L1 expression was heterogeneous across various BC tissue layers in the 3D space. Notably, there were six cases (30%) wherein PD-L1 expression levels along different layers crossed the 1% threshold for admitting patients to PD-1/PD-L1 inhibitors. The average PD-L1 expression in 3D space was different from that of traditional immunohistochemistry (IHC) in eight cases (40%). Pending further standardization and optimization, we expect that our technology will become a valuable addition for assessing PD-L1 expression in patients with BC.

CONCLUSION

Via a single round of immunofluorescence imaging, our approach may provide a considerable improvement in patient stratification for cancer immunotherapy as compared with standard techniques.

Moral distress and psychological status among healthcare workers in a newly established paediatric intensive care unit

INTRODUCTION

Healthcare workers in intensive care units often experience moral distress, depression, and stress-related symptoms. These conditions can lower staff retention and influence the quality of patient care. This study aimed to evaluate the prevalence of moral distress and psychological status among healthcare workers in a newly established paediatric intensive care unit (PICU) in Hong Kong.

METHODS

A cross-sectional questionnaire survey was conducted in the PICU of the Hong Kong Children's Hospital; healthcare workers (doctors, nurses and allied health professionals) were invited to participate. The Revised Moral Distress Scale (MDS-R) Paediatric Version and Depression Anxiety and Stress Scale-21 items were used to assess moral distress and psychological status, respectively. Demographic characteristics were examined in relation to moral distress, depression, anxiety, and stress scores to identify risk factors for poor psychological outcomes. Correlations of moral distress with depression, anxiety, and stress were examined.

RESULTS

Forty-six healthcare workers completed the survey. The overall median MDS-R moral distress score was 71. Nurses had a significantly higher median moral distress score, compared with doctors and allied health professionals (102 vs 47 vs 20). Nurses also had the highest median anxiety and stress scores (11 and 20, respectively). Moral distress scores were correlated with depression (r=0.445; P=0.002) and anxiety scores (r=0.417; P<0.05). Healthcare workers intending to quit their jobs had significantly higher moral distress scores (P<0.05).

CONCLUSION

Among PICU healthcare workers, nurses had the highest level of moral distress. Moral distress was associated with greater depression, anxiety, and intention to quit. Healthcare workers need support and a sustainable working environment to cope with moral distress.

Imaging findings of granular cell tumours of the head and neck

AIM

To review the imaging characteristics of granular cell tumours in the head and neck and assess their associations with pathological findings.

MATERIALS AND METHODS

Eleven patients (10 [91%] women, mean age 43 years) with histopathologically confirmed granular cell tumours were included in this study. Preoperative imaging studies were performed, including computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound. The location of the tumours, their imaging features, and histopathological findings were analysed.

RESULTS

Among the 11 granular cell tumours, four (36%), three (27%), and two (18%) tumours were found in the submucosal layer, subcutaneous layer, and intramuscular area, respectively. On CT, all tumours exhibited homogeneous iso-attenuating enhancement compared with adjacent muscle, and nine out of the 11 tumours (81%) demonstrated well-defined margins. On T2-weighted imaging (T2WI), four out of five tumours (80%) demonstrated iso-signal intensity compared with adjacent muscles, and four tumours (80%) exhibited homogeneous signal intensity. The apparent diffusion coefficient (ADC) values ranged from 0.68-0.81 × 10-3 mm2/s. Histopathological examination revealed densely packed tumour cells with variable amounts of fibrous stroma.

CONCLUSION

Granular cell tumours were characterised by well-defined and iso-signals on T2WI and low mean ADC values, and were predominantly located in the submucosal, subcutaneous, or intramuscular areas in middle-aged women. The characteristic locations, demographic characteristics, and imaging findings can help to differentiate granular cell tumours from other soft-tissue tumours in the head and neck.

Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at sqrt[s_{NN}]=200 GeV

The polarization of Λ and Λ[over ¯] hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sqrt[s_{NN}]=200  GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p_{T} dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and p_{T} dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

The Role of Postoperative Radiotherapy in T4 Rectal Cancer with Synchronous Distant Metastasis

PURPOSE/OBJECTIVE(S)

Studieson the role of surgery and local treatment in M1 rectal cancer have been actively studied recently. However, there is still controversy because no significant results have been reported for local control. The purpose of this study was to analyze the local control rates of postoperative radiotherapy for tumor stage T4 in M1 rectal cancer.

MATERIALS/METHODS

We investigated local recurrence after surgery for M1 rectal cancer that was operated at Seoul St. Mary's Hospital between 1995 and 2021. Locoregional recurrence rates were compared in patients who received postoperative pelvic radiotherapy and those who did not. In addition, an analytical comparison was performed only for patients with T4 rectal cancer. Statistical analysis was performed using the log rank test, and a p-value of less than 0.05 was considered significant.

RESULTS

During the investigation period, a total of 206 patients underwent surgery for M1 rectal cancer. There were 55 patients with T4 tumor stage. Of the 55 patients, 11 patients received radiotherapy after surgery, and 44 patients received systemic treatment such as chemotherapy after surgery without radiotherapy. During a median follow-up of 22 months, locoregional recurrence occurred in 1 (RT group) and 25 (no RT group) patients, respectively. Log-rank analysis of locoregional recurrence showed a significant difference between the two groups (p- value = 0.008). Death occurred in 10 (RT group) and 38 (no RT group) patients, respectively. The 2-year locoregional recurrence free-survival rates were 45.5% and 53.0%, respectively, and there was no significant difference between the two groups in the log-rank analysis.

CONCLUSION

Pelvic radiotherapy could be expected to improve locoregional recurrence in stage T4 of rectal cancer with synchronous distant metastasis. It would be warranted to prove this in a large-scale prospective study.

A Prospective Study Assessing the Efficacy and Toxicity of Stereotactic Body Radiation Therapy for Oligometastatic Bone Metastases

PURPOSE/OBJECTIVE(S)

Stereotactic body radiation therapy (SBRT) is a promising treatment for oligometastatic disease in bone due to its delivery of high dose to target tissue and minimal dose to surrounding tissue. The purpose of this study is to assess efficacy and toxicity of this treatment in patients with previously unirradiated oligometastatic bony disease.

MATERIALS/METHODS

In this prospective phase II trial, patients with oligometastatic bone disease, defined as ≤3 active sites of disease, were treated with SBRT at one of two academic institutions between December 2016 and May 2019. Local progression-free survival (LPFS), progression-free survival (PFS), prostatic specific antigen (PSA) progression, and overall survival (OS) were reported. Treatment-related toxicity was also reported.

RESULTS

A total of 98 patients and 131 lesions arising from various tumor histologies were included in this study. The median age of patients enrolled in the study was 72.8 years (80.6% male, 19.4% female). Median follow-up was 26.7 months. The most common histology was prostate cancer (68.4%, 67/98). The most common dose prescriptions were 27/30 Gy in 3 fractions (26.0%, 34/131), 30 Gy in 5 fractions (19.1%, 25/131), or 30/35 Gy in 5 fractions (16.0%, 21/131). Multiple doses per treatment regimen reflect dose painting employing the lower dose to the clinical target volume (CTV) and higher dose to the gross tumor volume (GTV). Four patients (4.1%, 4/98) experienced local progression at one site for each patient (3.1%, 4/131). Among patients who progressed locally, the median time to local recurrence was 25.8 months (31.0 months among prostate cancer patients, N = 2, and 14.5 months among non-prostate cancer patients, N = 2). Among the entire cohort, 2-year LPFS (including death without local progression) was 85.0%, 2-year PFS (including deaths as well as local, distant, and PSA-based progression) was 47.0%, and 2-year OS was 87.5%. Twenty-seven patients (27.6%, 27/98) developed treatment-related toxicities, and most were Grade 1 (19.4%, 19/98) and 2 (4.1%, 4/98). Four patients (4.1%, 4/98) developed Grade 3 toxicities; there were no Grade 4 toxicities. The most common toxicity was fatigue (10.2%, 10/98). Of 68 treated spine metastases, there were four (5.9%, 4/68) vertebral fractures. Among these four patients, median time to fracture was 23.5 months (range 14.2-39.2 months).

CONCLUSION

Our study supports existing literature in showing that SBRT is effective and tolerable in patients with oligometastatic bone disease. Larger phase III trials are necessary and reasonable to determine long-term efficacy and toxicities.

Prognostic Value of Depth of Invasion in Squamous Cell Carcinoma of the Oral Cavity of Size 4 cm or Less

PURPOSE/OBJECTIVE(S)

We aimed to evaluate the role of the depth of invasion (DOI) as an independent prognostic factor in the absence of other adverse features in squamous cell carcinoma (SqCC) of the oral cavity with a size of 4 cm or less.

MATERIALS/METHODS

We performed a retrospective analysis in a multi-institutional cohort of patients with oral cavity SqCC, size of 4 cm or less. We included those who were treated with upfront surgery with negative resection margins from 2010 to 2021 and those with one or no nodal metastasis. Those who were treated with postoperative radiotherapy were excluded. The DOI and other adverse features, such as close resection margins, lymphovascular invasion, perineural invasion, and nodal metastasis, were evaluated in univariate and multivariate analyses for their association with locoregional recurrence (LRR).

RESULTS

A total of 155 patients were included with a median follow-up of 23.7 months. 56 patients (36.1%) had DOI greater than 5 mm. 26 patients (16.8%) experienced LRR and one experienced distant metastasis. Multivariate analysis showed that DOI was the only prognostic factor associated with a higher rate of LRF (p = 0.004). The 2-year LRF rates of those with DOI ≤ 5 mm and DOI > 5mm were 4.7% and 30.3%, respectively.

CONCLUSION

This study implies that DOI greater than 5 mm may be an independent prognostic factor of the SqCC of the OCC and may be indicated for adjuvant radiotherapy.